1. Field of the Invention
The present invention relates to video processing, and, in particular, to the insertion and recovery of watermark data into and from video works.
2. Description of the Related Art
A major barrier to the development and deployment of distribution channels for motion imagery content (e.g., video download, digital cinema) is the concern of content providers that their copyrighted material may be copied and then subsequently distributed without appropriate authorization. Encryption is an important component of a Digital Rights Management (DRM) approach to controlling access to the content. However, once access has been granted, the decrypted content is left unprotected. Thus encryption alone cannot prevent all instances of theft. Persistent access control methods that rely on proprietary file formats and the use of compliant devices have been proposed, but ultimately all video must be converted to pixel brightness and color for display. At this point, the video is vulnerable.
Given these potential leaks, a content owner needs forensic tools that enable the tracking of unauthorized copies back to the party who licensed the use of the content, and who was responsible for preventing its further distribution. The ability of the content owners to identify the exact distribution point at which material was stolen can be used as a tool to identify the responsible parties and can act as a deterrent to such theft. A superimposed pattern on the digital imagery content uniquely identifying, in the content itself, the licensee of that copy of the content can serve this purpose. Such a watermark will give content owners a powerful forensic tool against piracy.
Consistent with those stated by SMPTE DC28.4 for their Download Watermark and Exhibition Watermark, a forensic watermark used for purchaser identification should have the following properties:                1. It should satisfy the high-fidelity requirements of the content owners.        2. Exhibition watermarks should be robust to the combination of exhibition capture and compression.        3. Exhibition watermarks should be secure against unauthorized removal and unauthorized embedding.Of the three properties listed above, no existing watermarking algorithm has yet demonstrated simultaneously acceptable performance in all three—fidelity, robustness, and security. In addition to these three properties, a forensic watermark can have the following features:        a. Detection of the watermark can rely on the use of a reference. This reference may be the corresponding unmarked video or a data vector derived from the unmarked video.        b. Detection is allowed to be an expensive process, since there will be few detectors, few applications of the detectors, and the nature of detection is such that it need not be done in real time.        